Nicola J. Allen

Research

Allen's lab investigates the molecular pathways that lead to connections between neurons, known as synapses, in the developing brain. Her group focuses on signaling interactions between neurons and astrocytes, a class of star-shaped glial cell. Astrocytes constitute half of the cells in the brain, and astrocyte processes, the "arms" that project outward from the cells, surround the majority of neuronal synapses in the brain. This places them in an ideal location to be actively involved in synapse formation and maintenance and in the modulation of communication between neurons. In fact, in the absence of astrocytes, few functional connections form between developing neurons, while their presence profoundly increases the number of functional synapses.

Previous studies began to identify the molecular signals between neurons and astrocytes and showed that thrombospondins and glypicans, two protein families that are secreted from developing astrocytes, affect synapse formation. The hypothesis is that astrocytes play a crucial role in dictating synapse formation and function via the release of specific proteins that determine the type of synapse that will form, and the strength of that synapse.

The current goal of the lab is to further investigate how these two protein families promote synapse formation, by identifying the neuronal receptors and cellular signaling pathways involved, and to understand how they interact to determine what type of synapse is formed. In addition, they will continue to use biochemical and molecular techniques to identify other ways that astrocytes influence distinct aspects of synapse formation and maturation and how they control the types of synapses that develop.

The pathways they identify will be investigated for roles in neurodevelopmental disorders, such as autism, that are caused by defects in synapse formation and function. In future studies, they will explore whether these developmental findings can be used to address diseases such as stroke, by promoting the repair of synaptic connections following injury.

"Neurons in the brain are connected by billions of synapses,
the points of communication between nerve cells. I want
to know what controls when and where these synapses are
formed, and how synaptic connections are modified to allow
memories to be stored."

Allen's lab investigates the molecular pathways
that lead to connections between
neurons, known as synapses, in the developing
brain. Her group focuses on signaling
interactions between neurons and astrocytes,
a class of star-shaped glial cells. Astrocytes
constitute half of the cells in the brain, and
astrocyte processes, the "arms" that project
outward from the cells, surround the majority
of neuronal synapses. This places them
in an ideal location to be actively involved
in synapse formation and maintenance and
in the modulation of communication between
neurons. In fact, in the absence of
astrocytes, few functional connections form
between developing neurons, while their
presence profoundly increases the number of
functional synapses.

Previous studies began to identify the molecular
signals between neurons and astrocytes
and showed that thrombospondins and glypicans,
two protein families that are secreted
from developing astrocytes, affect synapse
formation. The hypothesis is that astrocytes
play a crucial role in dictating synapse
formation and function via the release of
specific proteins that determine the type of
synapse that will form, and the strength of
that connection.

The current goal of the lab is to further
investigate how these two protein families
promote synapse formation, by identifying
the neuronal receptors and cellular signaling
pathways involved, and to understand how
they interact to determine what type of
synapse is formed. In addition, they will
continue to use biochemical and molecular
techniques to identify other ways that astrocytes
influence distinct aspects of synapse
formation and maturation and how they
control the types of connections that develop.

The pathways they identify will be investigated
for roles in neurodevelopmental disorders,
such as autism, that are caused by defects
in synapse formation and function. In future
studies, they will explore whether these developmental
findings can be used to address
diseases such as stroke by promoting the
repair of neural connections following injury.